Known electrolyte solutions used in electrochemical devices such as lithium ion secondary batteries include electrolyte solutions containing a fluorinated organophosphate.
For example, in order to provide a lithium secondary battery having excellent charge and discharge cycle characteristics as a result of restraining the reaction between the negative electrode and a non-aqueous electrolyte solution when charged and discharged, Patent Literature 1 discloses a lithium secondary battery including a positive electrode, a negative electrode, and a non-aqueous electrolyte solution containing a solute dissolved in a non-aqueous solvent, wherein the negative electrode is formed from a negative electrode material containing aluminum and the non-aqueous solvent is mixed with at least one selected from the group consisting of fluorinated organophosphates and fluorinated organophosphites.
Patent Literature 2 discloses a non-aqueous electrolyte battery including a positive electrode that contains a lithium-containing polyanionic metal complex compound wherein the non-aqueous electrolyte has incombustibility while having excellent high-rate discharge performance and cycle performance. The non-aqueous electrolyte battery is a non-aqueous electrolyte secondary battery and characteristically contains one or more fluorinated organophosphate compounds in which the end structure of an alkyl group is represented by CF3 and one or more fluorinated organophosphate compounds in which the end structure of an alkyl group is represented by CF2H.
Patent Literature 3 discloses an incombustible non-aqueous electrolyte solution having high solubility of an electrolyte salt, a large discharge capacity, and excellent charge and discharge cycle characteristics, and containing an organic solvent (II) which contains 0.5 to 30 vol % of a fluorine-containing organophosphate (I) represented by O═P(CH2Rf)3 and an electrolyte salt (III).
Patent Literature 4 discloses a secondary battery which can work for a long time, wherein an electrolyte solution used therein includes a liquid medium which is less likely to generate carbon dioxide at a concentration of 10 to 80 vol %, and discloses fluorinated organophosphate compounds as examples of the liquid medium which is less likely to generate carbon dioxide.
Patent Literature 5 discloses a non-aqueous electrolyte solution for non-aqueous secondary batteries which has high ion conductivity and is capable of maintaining the performance for a long time, and contains LiPF6 as an electrolyte, a cyclic carbonate as a solvent, and a fluorine-containing organophosphate represented by O═P(CH2Rf)3 in an amount 0.1 to 2 times (mole ratio) larger than the amount of LiPF6.